Dentin--a bony substance which serves as a
cushion for chewing forces.

Pulp--blood
vessels and nerves which nourish and give perception to the tooth.

Cementum--the
hard outer surface of the tooth where there is no enamel.

Periodontal
ligament--the connective tissue that attaches to both the
cementum and the jawbone anchoring the tooth.

It takes 14 months for a tooth to be completed in a human. The
process of tooth formation is called "a tiny marvel of design and
construction" (Scientific American,
August 2005, page 37). Six to seven weeks after conception when the
human head is being formed, tooth development begins. There are four
steps that have been identified in the design and engineering of human
teeth:

Mouth surface cells at the tooth location thicken slightly and
gene activity within its cells sends signals to underlying tissue which
surround the surface cells. This forms a tooth bud. This is done by
week seven or eight.

The thickened surface cells become a cap, and at the center of
this cap a structure forms called an enamel knot. This knot sends
signals to all other cells to direct their growth. This is accomplished
by the ninth week after conception.

The developing tooth has a bell shape with cells forming on the
top that will become enamel and cells under that which will become
dentin. This is completed by the fourteenth week.

Roots develop, completing their formation six to twelve months
after birth.

It is difficult to comprehend how all of these cells know how to do
what they do and when to do it. Scientists have been intercepting the
signals mentioned above, and they are now trying to see if they can
grow human teeth artificially to replace the false teeth that so many
of us know about, which are less than ideal. Sending signals and
controlling construction timing is a function of intelligent and
purposeful design--not chance. Our teeth are wonderfully designed and
planned, and their construction gives us insight to the wisdom in and
complexity of the mind of God.